Effect of micropore potassium-silicon-calcium (PSC) mineral fertilizer on rice growth and the characteristics of brown-humid soils

Pot experiments were carried out to study of effects of micropore potassium-silicon-calcium (PSC) mineral fertilizer (a national invention patented product) on rice growth, yield and soil physical and chemical characteristics in brown-humid soils. Five treatments were designed, i.e. zero fertilization (T1), conventional fertilization (T2), conventional fertilization plus micropore PSC mineral fertilizer at 4 g·pot^-1 (T3), conventional fertilization plus micropore PSC mineral fertilizer at 8 g·pot^-1 (T4), and conventional fertilization plus micropore PSC mineral fertilizer at 12 g·pot^-1 (T5). Compared with T2, results showed that the application of micropore PSC mineral fertilizer reduced soil bulk density by 0.04 g·cm^-3. It also increased soil porosity, pH and contents of soil available silicon and potassium by 1.8%, 0.1, 9.4~27.0 mg·kg^-1 and 10.6~39.7 mg·kg-1, respectively. Compared with T2, micropore PSC mineral fertilizer increased not only leaf chlorophyll content, but also rice flag leaf area by 4.8 cm². It also increased effective panicle numbers by 2.3~5.0 spike·pot^-1, 1000-grain weight by 0.1~1.9 g and average yield by 13.6%. Recovery rates of N, P, K increased by 0.6%~7.5%, 0.1%~1.5% and 8.5%~13.5%, respectively. Based on rice yield, the optimal recommended economic application rate of micropore PSC mineral fertilizer was 4 g·pot^-1 equivalent to 450 kg·hm^-2 in brown-humid soils.